Activision Blizzard Inc. is cutting ties with the videogame studio behind one of its biggest hits, a surprise move that knocked its stock down more than 6.5% and adds to questions about whether the company has a robust enough slate of games for 2019.

Bungie Inc., the Bellevue, Wash., development studio responsible for the science-fiction shooter “Destiny,” is purchasing the publishing rights for the franchise, Activision Blizzard said Thursday. Terms of the deal weren’t disclosed.